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Too Tight or Too Loose
The chain drive works well because the chain is just
the right length. But what happens when the chain is
too tight?
Experiment 27
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You will need: solar transporter
Instructions
Remove one chain link. What happens?
Results
The chain pulls with difficulty, and even bends the
axles a little. When that happens, the axles lose their
play and can’t turn easily. The engine’s power is no
longer enough to move the vehicle.
And what about the opposite? What effect does a
chain have if it’s too long?
Experiment 28
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You will need: solar transporter, at least five extra
chain links (29)
Instructions
Lengthen the chain by five links to 58. What happens
now?
Results
The engine does run, and the chain drive works, but
the chain flops around. There is a risk that it might
get tangled up and twisted, and jump off the sprocket
wheels. Then, your model would certainly not work
well any longer.
So when you assemble your models, be sure that
the chain is neither too tight nor too loose. That will
ensure that they will run well.
Caterpillar Tracks
Chains can be used for other things besides drive
chains. With many kinds of vehicles, they take the
place of regular wheels. Examples of this are caterpil-
lar tractors, dredgers, or some military vehicles.
Chains that are used instead of wheels to move a
vehicle across the ground are sometimes called cat-
erpillar tracks. We will try switching out the wheels for
caterpillar tracks and then compare the performance
of the tracks with that of the wheels.
To equip your vehicle with caterpillar tracks, remove the cargo bed and
switch out the tires for large sprocket wheels.
1. First, remove the four wheels. The tires will be replaced by sprocket
wheels and caterpillar tracks.
2. Then dismantle the cargo bed, removing the base plate and the two
short frames supporting it. Also pull out the eight anchor pins from the
large frames.
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